As a high mounted stop lamp, etc. provided at the rear of the vehicle, an LED or the like has been utilized because it requires less electric power consumption and emits light at high luminance. As shown in FIG. 6, this high mounted stop lamp comprises a circuit formed by a plurality of parallel connected LED groups L1˜L6, each including the same number of LEDs (four in FIG. 6) connected in series. With this arrangement, even if one LED (any one of LEDs D1˜D24) malfunctions, the rest of the LED groups L1˜L6 satisfies the demand luminous energy regulated by law.
There is a lighting device with a circuit arrangement similar to this high mounted stop lamp, wherein a main light source that emits light with greater luminous energy in order to satisfy the regulation by law and an auxiliary light source that is used for accessories to dress up the vehicular design are connected in parallel.
This kind of lighting device has been adapted to side turn lights for indicating a change of the direction of the vehicle.
Generally, the side turn lights are provided at side surfaces of the vehicle, and in this instance, the lighting device having the aforementioned circuit arrangement is not required. However, in recent years, the side turn lights have been provided at the outer mirrors instead of being provided at both side surfaces of the vehicle body for the purpose of dressing up the vehicle, and therefore the lighting device has been applied for outer mirrors. In other words, in order to be visible from the sides and the rear of the vehicle, the main light source emitting a sufficient luminous energy that satisfies the regulation is arranged at both edges of the outer mirrors, remotely from and outside of the vehicle compartment, and the auxiliary light source for accessories is arranged at a front of each outer mirror in a position parallel to the main light source.
According to the arrangement of the circuit where the main light source and the auxiliary light source are merely connected in parallel, even if one of the light sources malfunctions, the emission of light is continued by the other light source. Therefore, it is difficult for the driver to recognize the malfunction of the side turn light. Especially, a problem arises when the main light source is run down, because the auxiliary light source continuously emits light with the luminous energy unsatisfying the regulation and the driver may misunderstand that the side turn lights function normally.
The technological problem to be solved by the present invention should be focused in this point, and the object of the invention is to provide a light emitting circuit and a lighting device for a vehicle, which are particularly used for a side turn light provided at an outer mirror of the vehicle, and which stops the emission of light of the auxiliary light source when the main light source is run down so that the run down of the main light source is reliably informed to the driver.